A rank 2 characterization of twinnings

by Bernhard Mühlherr.

Abstract:
We show that a non-empty relation between the chambers of two buildings of the same type is the opposition relation of a twinning as soon as this holds for all its restrictions on opposite rank 2 residues.

Key words and phrases: Twin buildings, Opposition relation.

1991 Mathematics Subject Classification: 51E24 .

Published in: European Journal of Combinatorics

Contact: Bernhard.Muehlherr@Mathematik.Uni-Dortmund.DE